/*
 * Copyright (c) 2010 CommonsWare, LLC
 * Portions Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.commonsware.cwac.tlv;

import sw6.visualschedule.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;

public class TouchListView extends ListView {
    private ImageView mDragView;
    private WindowManager mWindowManager;
    private WindowManager.LayoutParams mWindowParams;
    private int mDragPos;      // which item is being dragged
    private int mFirstDragPos; // where was the dragged item originally
    private int mDragPoint;    // at what offset inside the item did the user grab it
    private int mCoordOffset;  // the difference between screen coordinates and coordinates in this view
    private DragListener mDragListener;
    private DropListener mDropListener;
    private RemoveListener mRemoveListener;
    private int mUpperBound;
    private int mLowerBound;
    private int mHeight;
    private GestureDetector mGestureDetector;
    public static final int FLING = 0;
    public static final int SLIDE_RIGHT = 1;
    public static final int SLIDE_LEFT = 2;
    private int mRemoveMode = -1;
    private Rect mTempRect = new Rect();
    private Bitmap mDragBitmap;
    private final int mTouchSlop;
    private int mItemHeightNormal=-1;
    private int mItemHeightExpanded=-1;
    private int grabberId=-1;
    private int dragndropBackgroundColor=0x00000000; 

    public TouchListView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }
    
    public TouchListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        
        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
        
        if (attrs!=null) {
            TypedArray a=getContext()
                                        .obtainStyledAttributes(attrs,
                                                                                            R.styleable.TouchListView,
                                                                                            0, 0);
        
            mItemHeightNormal=a.getDimensionPixelSize(R.styleable.TouchListView_normal_height, 0);
            mItemHeightExpanded=a.getDimensionPixelSize(R.styleable.TouchListView_expanded_height, mItemHeightNormal);
            grabberId=a.getResourceId(R.styleable.TouchListView_grabber, -1);            
            dragndropBackgroundColor=a.getColor(R.styleable.TouchListView_dragndrop_background, 0x00000000);
            mRemoveMode=a.getInt(R.styleable.TouchListView_remove_mode, -1);
            
            a.recycle();
        }
  }
    
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
            if (mRemoveListener != null && mGestureDetector == null) {
                    if (mRemoveMode == FLING) {
                            mGestureDetector = new GestureDetector(getContext(), new SimpleOnGestureListener() {
                                    @Override
                                    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                                                    float velocityY) {
                                            if (mDragView != null) {
                                                    if (velocityX > 1000) {
                                                            Rect r = mTempRect;
                                                            mDragView.getDrawingRect(r);
                                                            if ( e2.getX() > r.right * 2 / 3) {
                                                                    // fast fling right with release near the right edge of the screen
                                                                    stopDragging();
                                                                    mRemoveListener.remove(mFirstDragPos);
                                                                    unExpandViews(true);
                                                            }
                                                    }
                                                    // flinging while dragging should have no effect
                                                    return true;
                                            }
                                            return false;
                                    }
                            });
                    }
            }
            if (mDragListener != null || mDropListener != null) {
                    switch (ev.getAction()) {
                            case MotionEvent.ACTION_DOWN:
                                    int x = (int) ev.getX();
                                    int y = (int) ev.getY();
                                    int itemnum = pointToPosition(x, y);
                                    if (itemnum == AdapterView.INVALID_POSITION) {
                                            break;
                                    }
                                    ViewGroup item = (ViewGroup) getChildAt(itemnum - getFirstVisiblePosition());
                                    mDragPoint = y - item.getTop();
                                    mCoordOffset = ((int)ev.getRawY()) - y;
                                    View dragger = item.findViewById(grabberId);
                                    Rect r = mTempRect;
//                                  dragger.getDrawingRect(r);
                                    
                                    r.left=dragger.getLeft();
                                    r.right=dragger.getRight();
                                    r.top=dragger.getTop();
                                    r.bottom=dragger.getBottom();                                   
                                    
                                    if ((r.left<x) && (x<r.right)) {
                                            item.setDrawingCacheEnabled(true);
                                            // Create a copy of the drawing cache so that it does not get recycled
                                            // by the framework when the list tries to clean up memory
                                            Bitmap bitmap = Bitmap.createBitmap(item.getDrawingCache());
                                            startDragging(bitmap, y);
                                            mDragPos = itemnum;
                                            mFirstDragPos = mDragPos;
                                            mHeight = getHeight();
                                            int touchSlop = mTouchSlop;
                                            mUpperBound = Math.min(y - touchSlop, mHeight / 3);
                                            mLowerBound = Math.max(y + touchSlop, mHeight * 2 /3);
                                            return false;
                                    }
                                    mDragView = null;
                                    break;
                    }
            }
            return super.onInterceptTouchEvent(ev);
    }
    
    /*
     * pointToPosition() doesn't consider invisible views, but we
     * need to, so implement a slightly different version.
     */
    private int myPointToPosition(int x, int y) {
            Rect frame = mTempRect;
            final int count = getChildCount();
            for (int i = count - 1; i >= 0; i--) {
                    final View child = getChildAt(i);
                    child.getHitRect(frame);
                    if (frame.contains(x, y)) {
                            return getFirstVisiblePosition() + i;
                    }
            }
            return INVALID_POSITION;
    }
    
    private int getItemForPosition(int y) {
            int adjustedy = y - mDragPoint - 32;
            int pos = myPointToPosition(0, adjustedy);
            if (pos >= 0) {
                    if (pos <= mFirstDragPos) {
                            pos += 1;
                    }
            } else if (adjustedy < 0) {
                    pos = 0;
            }
            return pos;
    }
    
    private void adjustScrollBounds(int y) {
            if (y >= mHeight / 3) {
                    mUpperBound = mHeight / 3;
            }
            if (y <= mHeight * 2 / 3) {
                    mLowerBound = mHeight * 2 / 3;
            }
    }

    /*
     * Restore size and visibility for all listitems
     */
    private void unExpandViews(boolean deletion) {
            for (int i = 0;; i++) {
                    View v = getChildAt(i);
                    if (v == null) {
                            if (deletion) {
                                    // HACK force update of mItemCount
                                    int position = getFirstVisiblePosition();
                                    int y = getChildAt(0).getTop();
                                    setAdapter(getAdapter());
                                    setSelectionFromTop(position, y);
                                    // end hack
                            }
                            layoutChildren(); // force children to be recreated where needed
                            v = getChildAt(i);
                            if (v == null) {
                                    break;
                            }
                    }
                    ViewGroup.LayoutParams params = v.getLayoutParams();
                    params.height = mItemHeightNormal;
                    v.setLayoutParams(params);
                    v.setVisibility(View.VISIBLE);
            }
    }
    
    /* Adjust visibility and size to make it appear as though
     * an item is being dragged around and other items are making
     * room for it:
     * If dropping the item would result in it still being in the
     * same place, then make the dragged listitem's size normal,
     * but make the item invisible.
     * Otherwise, if the dragged listitem is still on screen, make
     * it as small as possible and expand the item below the insert
     * point.
     * If the dragged item is not on screen, only expand the item
     * below the current insertpoint.
     */
    private void doExpansion() {
            int childnum = mDragPos - getFirstVisiblePosition();
            if (mDragPos > mFirstDragPos) {
                    childnum++;
            }

            View first = getChildAt(mFirstDragPos - getFirstVisiblePosition());

            for (int i = 0;; i++) {
                    View vv = getChildAt(i);
                    if (vv == null) {
                            break;
                    }
                    int height = mItemHeightNormal;
                    int visibility = View.VISIBLE;
                    if (vv.equals(first)) {
                            // processing the item that is being dragged
                            if (mDragPos == mFirstDragPos) {
                                    // hovering over the original location
                                    visibility = View.INVISIBLE;
                            } else {
                                    // not hovering over it
                                    height = 1;
                            }
                    } else if (i == childnum) {
                            if (mDragPos < getCount() - 1) {
                                    height = mItemHeightExpanded;
                            }
                    }
                    ViewGroup.LayoutParams params = vv.getLayoutParams();
                    params.height = height;
                    vv.setLayoutParams(params);
                    vv.setVisibility(visibility);
            }
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
            if (mGestureDetector != null) {
                    mGestureDetector.onTouchEvent(ev);
            }
            if ((mDragListener != null || mDropListener != null) && mDragView != null) {
                    int action = ev.getAction(); 
                    switch (action) {
                            case MotionEvent.ACTION_UP:
                            case MotionEvent.ACTION_CANCEL:
                                    Rect r = mTempRect;
                                    mDragView.getDrawingRect(r);
                                    stopDragging();
                                    
                                    if (mRemoveMode == SLIDE_RIGHT && ev.getX() > r.left+(r.width()*3/4)) {
                                            if (mRemoveListener != null) {
                                                    mRemoveListener.remove(mFirstDragPos);
                                            }
                                            unExpandViews(true);
                                    } else if (mRemoveMode == SLIDE_LEFT && ev.getX() < r.left+(r.width()/4)) {
                                            if (mRemoveListener != null) {
                                                    mRemoveListener.remove(mFirstDragPos);
                                            }
                                            unExpandViews(true);
                                    } else {
                                            if (mDropListener != null && mDragPos >= 0 && mDragPos < getCount()) {
                                                    mDropListener.drop(mFirstDragPos, mDragPos);
                                            }
                                            unExpandViews(false);
                                    }
                                    break;
                                    
                            case MotionEvent.ACTION_DOWN:
                            case MotionEvent.ACTION_MOVE:
                                    int x = (int) ev.getX();
                                    int y = (int) ev.getY();
                                    dragView(x, y);
                                    int itemnum = getItemForPosition(y);
                                    if (itemnum >= 0) {
                                            if (action == MotionEvent.ACTION_DOWN || itemnum != mDragPos) {
                                                    if (mDragListener != null) {
                                                            mDragListener.drag(mDragPos, itemnum);
                                                    }
                                                    mDragPos = itemnum;
                                                    doExpansion();
                                            }
                                            int speed = 0;
                                            adjustScrollBounds(y);
                                            if (y > mLowerBound) {
                                                    // scroll the list up a bit
                                                    speed = y > (mHeight + mLowerBound) / 2 ? 16 : 4;
                                            } else if (y < mUpperBound) {
                                                    // scroll the list down a bit
                                                    speed = y < mUpperBound / 2 ? -16 : -4;
                                            }
                                            if (speed != 0) {
                                                    int ref = pointToPosition(0, mHeight / 2);
                                                    if (ref == AdapterView.INVALID_POSITION) {
                                                            //we hit a divider or an invisible view, check somewhere else
                                                            ref = pointToPosition(0, mHeight / 2 + getDividerHeight() + 64);
                                                    }
                                                    View v = getChildAt(ref - getFirstVisiblePosition());
                                                    if (v!= null) {
                                                            int pos = v.getTop();
                                                            setSelectionFromTop(ref, pos - speed);
                                                    }
                                            }
                                    }
                                    break;
                    }
                    return true;
            }
            return super.onTouchEvent(ev);
    }
    
    private void startDragging(Bitmap bm, int y) {
            stopDragging();

            mWindowParams = new WindowManager.LayoutParams();
            mWindowParams.gravity = Gravity.TOP;
            mWindowParams.x = 0;
            mWindowParams.y = y - mDragPoint + mCoordOffset;

            mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
            mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
            mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                            | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                            | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                            | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;
            mWindowParams.format = PixelFormat.TRANSLUCENT;
            mWindowParams.windowAnimations = 0;
            
            ImageView v = new ImageView(getContext());
//        int backGroundColor = getContext().getResources().getColor(R.color.dragndrop_background);
            v.setBackgroundColor(dragndropBackgroundColor);
            v.setImageBitmap(bm);
            mDragBitmap = bm;

            mWindowManager = (WindowManager)getContext().getSystemService("window");
            mWindowManager.addView(v, mWindowParams);
            mDragView = v;
    }
    
    private void dragView(int x, int y) {
            float alpha = 1.0f;
            int width = mDragView.getWidth();
            
            if (mRemoveMode == SLIDE_RIGHT) {
                    if (x > width / 2) {
                            alpha = ((float)(width - x)) / (width / 2);
                    }
                    mWindowParams.alpha = alpha;
            }
            else if (mRemoveMode == SLIDE_LEFT) {
                    if (x < width / 2) {
                            alpha = ((float)x) / (width / 2);
                    }
                    mWindowParams.alpha = alpha;
            }
            mWindowParams.y = y - mDragPoint + mCoordOffset;
            mWindowManager.updateViewLayout(mDragView, mWindowParams);
    }
    
    private void stopDragging() {
            if (mDragView != null) {
                    WindowManager wm = (WindowManager)getContext().getSystemService("window");
                    wm.removeView(mDragView);
                    mDragView.setImageDrawable(null);
                    mDragView = null;
            }
            if (mDragBitmap != null) {
                    mDragBitmap.recycle();
                    mDragBitmap = null;
            }
    }
    
    public void setDragListener(DragListener l) {
            mDragListener = l;
    }
    
    public void setDropListener(DropListener l) {
            mDropListener = l;
    }
    
    public void setRemoveListener(RemoveListener l) {
            mRemoveListener = l;
    }

    public interface DragListener {
            void drag(int from, int to);
    }
    public interface DropListener {
            void drop(int from, int to);
    }
    public interface RemoveListener {
            void remove(int which);
    }
}
